engleski

Genotyping of the CYP2D6 A and B allelic variants by PCR-RFLP

The genetic polymorphism of the enzymes involved in the metabolism of drugs and environmental carcinogens has an important role in adverse therapeutic effects or prevalence of cancer. CYP2D6, the isoform of the cytochrome P-450 metabolizing more than 25 percent of most common drugs, has 16 different allelic variants identified to date. The mutant CYP2D6 A allele with A deletion in exon 5 and mutant CYP2D6 allele B1934A, splice site defect, are among the most common. The aim of the study was to develop a method for identification of CYP2D6 A and B gene mutations, and to assess their prevalence in a group of healthy subjects and patients with various disease etiologies. Genotyping of the CYP2D6 A and B alleles was performed on DNA isolated from the blood of diseased (n=37) and healthy (n=15) volunteers by PCR-RFLP method. Upon exon IV (B allele) and exon V (A allele) amplification, the PCR products thus obtained (355 bp and 270 bp, respectively) were cleaved by Mva I and Msp I restriction endonucleases, and genotype of each sample was determined by electrophoresis of the cleaving products on 3 percent agarose gel. Study results showed that among 15 healthy volunteers genotyped for A and B allele no had A allele, but 6 were detected to bear B allele. Genotyped as B allele, five (33 percent) of them were found to be heterozygous and one (7 percent) homozygous. In 35 patients genotyped for A and B alleles, there was only one with A allele and he was heterozygous. There were 14 patients with B allele, 12 (32 percent) of them heterozygous and two (5.4 percent) homozygous This preliminary results indicated the PCR-RFLP assay to be suitable for detecting the CYP2D6 A and B polymorphism as well as their zygosity. Since A/A or B/B homozygosity points to poor metabolizing capacity, and A or B heterozygosity to intermediate metabolizing capacity, these preliminary results suggest that further study should be focused on the relationship between the CYP2D6 polymorphism and therapy alteration or prevalence of cancer or chronic disease.

Genotyping; CYP2D6 A and B; PCR-RFLP

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